1. Field of the Invention
This invention relates in general to character recognition systems and relates more particularly to such systems having provision for resolving detected ambiguities in sensed characters.
2. Prior Art
A wide variety of pattern recognition systems are known in the art. Each such system optically receives data depicting a pattern to be recognized, and performs certain tasks on this pattern to compare it to known patterns in order to "recognize" the input pattern. A basic flow chart depicting a pattern recognition system is shown in FIG. 1. The input pattern is the pattern which is to be recognized. Digitizer 12 converts input pattern 11 to a series of bytes for storage in system memory 13. These bytes are typically binary in nature, reflecting the fact that input pattern 11 is basically a black and white figure. Digitizers are well known in the art and typically are used in such devices as facsimile machines, electronic duplicating machines (as opposed to optical photocopy machines) and optical character recognition systems of the prior art. Memory 13 can comprise any suitable memory device, including random access memories of well-known design. Segmentation 14 serves to divide the image data stored in memory 13 into individual characters. Such segmentation is known in the prior art, and is described, for example, in "Digital Picture Processing," Second Edition, Volume 2, Azriel Rosenfeld and Avinash C. Kak, Academic Press, 1982, specifically, Chapter 10 entitled "Segmentation".
Feature extraction 15 serves to transform each piece of data (i.e., each character) received from segmentation 14 into a standard predefined form for use by classification means 16, which in turn identifies each character as one of a known set of characters.
Classification means 16 can be any one of a number of prior art identification means typically used in pattern recognition systems, including, more specifically, optical character recognition systems. One such classification means suitable for use in accordance with the teachings of this invention is described in U.S. Pat. No. 4,259,661, issued Mar. 31, 1981 to Todd, entitled "Apparatus and Method for Recognizing a Pattern". Identification means 16 is also described in "Syntactic Pattern Recognition and Applications," K. S. Fu, Prentice Hall, Inc., 1982, specifically, Section 1.6, and Appendices A and B.
Postprocessing means 17 can be any one of a number of prior art postprocessing means typically used in pattern recognition systems, such as described in "n-Gram Statistics For Natural Language Understanding And Text Processing" Suen, IEEE "Transactions on Pattern Analysis and Machine Intelligence," Vol. PAMI-1, No. 2, pp. 164-172, April 1979.
Output means 18 serves to provide data output (typically ASCII, or the like) to external circuitry (not shown).